You were banned because you lost control of your account. Most likely your passwords for Myspace and your email were the same. When you gave away your password for Myspace, you also gave away access to your email and therefor your PbN account. Always check the url before ever entering your password. Every time.
What you need to do right now is change all accounts (email, myspace, bank, paypal, PbNation, etc) that use that password to a new and completely different password.
Nothing was hacked. You were just tricked into giving away your password and your passwords were the same for everything. Our standard practice is to ban an account when a user has lost control of it. That prevents the user from getting in even more trouble on our site.
If this is your first banned account, you are more than welcome to make a new PbNation account, but you need to be more careful when entering your password. Always check the url and make sure it is not a phishing site.
If you were ASM, go to the contact us page if you want to apply for an unban.
Read more about phishing here.